Shellac is the primary ingredient in the varnishes that I make and use. I dilute the shellac in grain alcohol and mix it with resins. I like working with shellac for several reasons, mainly because it is a natural product and is not harmful to my health like many of the other finishing options on the market. While it's not the toughest finish in the world, it's easy to repair and bring back to life, it looks great, and it ages wonderfully.
A friend recently passed along this video on the harvesting and processing of shellac. It's fascinating and informative. Mr. Velji, who made the video, really knows his stuff. If you're interested in a good source for shellac, or on learning how to French polish, I would highly recommend his site shellacfinishes.com, where he sells a variety of grades of shellac, as well as a DVD on the process of French polishing.